1. Field of the Invention
The present invention relates to a switch unit to be used for operating various devices such a powerwindow unit mounted on a vehicle such as a motor vehicle.
2. Description of the Related Art
A powerwindow unit up/down-operates a window glass installed at a door trim of a vehicle. Based on an operation signal from a switch unit provided on the door trim, the powerwindow unit drives a motor and so on for up/down-operating the window glass, thereby opening and closing a window.
The above switch unit has a knob as a operative body which is swingingly operably provided, a printed circuit board, and a decorative members to outline the printed circuit board and to make the knob exposed. A pair of first switch portions being abuttable on respective end portions of the knob are provided on the printed circuit board. Each first switch portion has both of a first contact portion provided on the printed circuit board and a first contacting member being contactable and discontactable with the first contact portion.
Between one first contacting member and one end portion of the knob provided are a returning spring and a pressing pin, which pressing pin presses one first contacting member toward the printed circuit board when one end portion of the knob is pushed toward the printed circuit board. Also, between the other first contacting member and the other end portion of the knob provided are a returning spring and a pressing pin, which pressing pin presses the other first contacting member toward the printed circuit board when the other end portion of the knob is pushed toward the printed circuit board. On the other hand, each returning spring returns the knob in an initial state.
According to the above-described structure of the conventional switch unit, when one end portion of the knob is pushed toward the printed circuit board, one first contacting member is pressed through the pressing pin and comes into contact with one first contact portion. Then, one first contact portion outputs a signal, for example, to raise the window glass toward the powerwindow unit.
On the other hand, when the other end portion of the knob is pushed toward the printed circuit board, the other first contacting member is pressed through the pressing pin and comes into contact with the other first contact portion. Then, the other first contact portion outputs a signal, for example, to lower the window glass toward the powerwindow unit.
And, when the pushing operation of one end portion or the other end portion of the knob is removed, one end portion or the other end portion of the knob returns to each initial state by means of each returning spring, whereby the output signal from each contact portion stops.
With respect to the above conventional switch unit, rolling of the knob would arise during the pushing operation, which would cause an un-smooth up/down operation of the window glass.
Otherwise, a switch unit having a pair of second switch portions, which are arranged apart from a line connecting the first switch portions and nearer a swing center of the knob than the first switch portions, has been used. In this switch unit, the second switch portions are also provided on a printed circuit board. Each second switch portion has both of a second contact portion provided on the printed circuit board and a second contacting member being contactable and discontactable with the second contact portion.
In this switch unit having the first switch portions and the second switch portions, when one or the other second contacting member is put into contact with one or the other second contact point, respectively, while one or the other first contacting member is put into contact with one or the other first contact point, respectively, the window glass goes up or down to top or bottom dead point, respectively.
With respect to this conventional switch unit, rolling of the knob would still arise during the pushing operation, which would also cause an un-smooth up/down operation of the window glass.